U.S. Pat. No. 4,001,742 filed Jan. 4, 1977 entitled "Circuit Breaker Having Improved Operating Mechanism" describes a circuit breaker capable of interrupting several thousand amperes of circuit current at several hundred volts potential. As described therein, the operating mechanism is in the form of a pair of powerful operating springs that are restrained from separating the circuit breaker contacts by means of a latching system. Once the operating mechanism has responded to separate the contacts, the operating springs must be recharged to supply sufficient motive force to the movable contact arms that carry the contacts.
U.S. patent application Ser. No. 08/202,140 filed Feb. 25, 1994 entitled "Operating mechanism for high ampere-rated circuit breaker" describes an operating mechanism capable of immediately closing the circuit breaker operating mechanism to reclose the contacts without having to recharge the circuit breaker operating springs immediately after opening the circuit breaker contacts.
U.S. patent application Ser. No. 08/203,062 filed Feb. 28, 1994 entitled "Rating module unit for high ampere-rated circuit breaker" describes a circuit breaker closing spring modular unit whereby the circuit breaker operating springs are contained within a separate unit from the operating mechanism and can be installed within the circuit breaker enclosure without disturbing the operating mechanism assembly.
U.S. patent application Ser. No. 08/214,522 filed Mar. 18, 1994 entitled "Handle operator assembly for high ampere-rated circuit breaker" describes a handle operator unit capable of generating large spring charging forces by means of an externally-accessible manually operated handle. A ratchet and pawl assembly allows the manually-applied charging forces to be applied to the operating springs. Once the circuit breaker operating mechanism closing springs are fully-charged, some means must be employed to release the pawl to allow the closing springs to become fully operational.
U.S. patent application Ser. No. 08/218,287 filed Mar. 28, 1994 entitled "A Latching Arrangement for High Ampere-rated Circuit Breaker Operating Springs" describes a two-stage latching arrangement that controls the retention and release of a ratchet pawl to retain and discharge the operating springs.
To prevent the circuit breaker operating mechanism from releasing the operating springs when the circuit breaker contacts are already closed, complex interlock schemes are usually interposed between the circuit breaker closing system and the operating mechanism.
This invention proposes a simple and efficient interlock arrangement to automatically retain the circuit breaker operating springs until the circuit breaker contacts are in the open condition.